JP2004502510A - Improvement of intraocular lens by GCIB - Google Patents

Abstract

An atomic level surface smoothing process for smoothing the outer edge of the IOL (10) using the GCIB (100) to reduce the edge phenomenon and the resulting glare phenomenon is disclosed. Furthermore, in order to improve the adhesion of the IOL (10) to the ocular sac, the present invention smoothes the front and / or the rear of the IOL (10) at the atomic level using the GCIB (100), and performs cell ingrowth. And the resulting secondary cataract. The surface smoothed with GCIB (100) reduces the adhesion of foreign substances to the surface, reduces microscopic irregularities present on the surface of IOL (10), and also reduces inflammation of the eye.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
FIELD OF THE INVENTION The present invention relates to medical devices such as lenses, and more particularly, to a method and system for improving the surface smoothness of an intraocular lens utilizing gas cluster ion beam (GCIB) technology.
[0002]
[Prior art]
BACKGROUND OF THE INVENTION With the use of intraocular lenses (IOLs) in cataract surgery, vision impairment symptoms may remain postoperatively. Postoperative clouding of IOL, which can be called secondary cataract, is the most frequent symptom, accounting for 30% to 50% of all IOL implantation surgery. Secondary cataracts are usually due to posterior migration of lens epithelial cells from the equator of the eye to the area between the original lens (lens) capsule and the IOL.
[0003]
In addition, acute or chronic inflammatory reactions due to compatibility with the IOL, which can lead to the formation of reactive objects that cause inflammatory responses (eg, increased vascular permeability, enhanced chemotaxis and increased phagocytosis, etc.) Can also occur. In addition, in some IOL patients, an "edge phenomenon" occurs, which is a major cause of explants in the intraocular lens. This edge phenomenon is caused by a corner outer rough edge that diffuses light at the edge portion. The light does not focus on the retina and causes glare. Despite the development of lens extraction techniques and studies of lens material replacement, cataract surgery frequently causes postoperative visual impairment.
[0004]
[Problems to be solved by the invention]
Accordingly, one object of the present invention is to provide an atomic level surface smoothing treatment of an intraocular lens.
[0005]
It is another object of the present invention to improve the surface of an intraocular lens by a gas cluster ion beam and reduce visual impairment by using such a lens.
[0006]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The foregoing and other objects and advantages of the present invention are achieved by the present invention described below.
[0007]
The present invention provides a GCIB-based intraocular lens (IOL) surface improvement to smooth the posterior and anterior surfaces of the IOL and its edges. This smoothing prevents migration of epithelial cells, improves the compatibility of the lens surface, and reduces postoperative damage. Reducing postoperative disability saves medical costs and reduces patient suffering.
[0008]
The present invention performs an atomic level surface smoothing process using GCIB to make the outer edge of the IOL smooth and round, thereby suppressing the "edge phenomenon" and the glare phenomenon. Furthermore, the present invention uses GCIB to perform an atomic level surface smoothing process, smoothes the posterior and / or anterior surface of the IOL to improve the adhesion of the IOL to the eye capsule, and prevents the ingrowth of cells. And reduce the occurrence of secondary cataracts. The surface smoothed by GCIB reduces the attachment of foreign objects to the surface and also reduces the onset of inflammation by reducing the micro-roughness of the IOL surface that was previously inevitable.
[0009]
To assist in understanding the invention, the invention will be described with reference to the accompanying drawings and detailed description.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Detailed Description of Preferred Methods and Examples Charged atoms or beams, which are energy ion beams accelerated under high-pressure vacuum conditions, are widely used for forming semiconductor device junctions, planarizing by sputtering, and improving thin film characteristics. . Gas cluster ions are formed of a number of weakly bonded atoms or molecules that share a common charge and are accelerated at high pressure to have a high total energy. Cluster ions are split by collision, and the entire energy of the cluster is distributed among the constituent atoms. Due to this energy distribution, the atoms are individually in a much lower energy state than normal or non-cluster ions, and the atoms only penetrate the surface much shallower. Since the surface sputtering effect requires more energy than the corresponding effect normally generated by ions, the present invention can provide a fine surface smoothing treatment that cannot be achieved by other methods.
[0011]
The concept of gas cluster ion beam (GCIB) processing was introduced about ten years ago. The use of GCIB for dry etching, cleaning and material smoothing is known and described, for example, in Exit et al., US Pat. No. 5,814,194, “Method of Treating Substrate Surfaces” (1998). It is possible to form ionized clusters containing thousands of gas atoms or molecules, and to apply energy of about several thousand electron volts. It has a degree of energy. For example, from the teachings of Yamada U.S. Pat. No. 5,459,326, it is known that such individual atoms do not have enough energy to penetrate deeper into the surface and cause internal damage, unlike plasma treatment. ing. In any case, the cluster itself has sufficient energy (thousands of electron volts) and can effectively etch, smooth or clean the hard surface.
[0012]
Since the energy of the individual atoms in the gas cluster ions is as low as a few electron volts, the atoms penetrate at most a few atomic layers of the target surface during collision. This shallow penetration is because the total energy carried by all cluster ions is consumed in the very shallow region of the upper surface layer in about ^10-12 seconds. This is different from the case of ion implantation. Normal ions are used in ion implantation, the purpose of which is to penetrate the ions into the material, the intensity of which changes the surface properties of the material, sometimes to the extent of penetrating thousands of angstroms. Due to the high total energy of the cluster ions and the minimal reaction region, the emission energy intensity at the collision site is much higher than the treatment with ordinary ions.
[0013]
This will be described with reference to FIG. FIG. 1 illustrates a gas cluster ion beam (GCIB) processor 100 of the present invention for surface smoothing of an IOL 10. The processor 100 includes a vacuum vessel 102 divided into three communicating chambers, a source chamber 104, an ionization / acceleration chamber 106, and a unique IOL 10 capable of positioning the IOL 10 for uniform smoothing with a gas cluster ion beam. And a processing chamber 108 including a target object holder 150 in the form.
[0014]
In the smoothing method of the present invention, these three chambers are evacuated to an appropriate pressure by vacuum pump systems 146a, 146b, 146c, respectively. A condensable gas source 112 (e.g., argon or N2) stored in a cylinder 111 is introduced under pressure through a gas meter valve 113 and a gas supply line 114 into a retention chamber 116, where the pressure is reduced to a low pressure by a suitably shaped nozzle 110. It is jetted and generates an ultrasonic gas jet 118. A part of the gas jet 118 becomes a plurality of clusters by cooling by the jet flow. Each cluster consists of weakly bonded atoms or molecules. The gas skimmer aperture 120 partially separates gas molecules that are not cluster jets from the cluster jets and reduces the pressure in downstream areas where high pressures are disadvantageous (eg, ionizer 122, high pressure electrode 126, processing chamber 108). Suitable enrichable gas sources 112 include argon, nitrogen, carbon dioxide, and the like.
[0015]
After the supersonic gas jet 118 containing the gas clusters is formed, the clusters are ionized in the ionizer 122. The ionizer 122 is typically an electron impact ionizer that generates thermionic electrons from the incandescent filament 124, accelerates the electrons to provide directionality, impinges on the gas clusters of the gas jet 118, and passes the jet through the ionizer 122. Electron collisions generate electrons from the clusters, causing some of the clusters to become cations. An appropriately biased high voltage electrode set 126 pulls cluster ions from the ionizer 122 to form a beam and accelerates them (typically from 1 K electron volts to tens of K electron volts) to impart the desired energy to the cluster ions. Focus processing to form a GCIB 128 having an initial path 154. Filament power supply 136 provides _{V F,} to heat the ionizer filament. Anode power supply 134 provides _VA to accelerate thermionic electrons emitted from filament 124 and impinge on clusters containing gas jets 118 to generate ions. Deriving power 138 provides _{V E,} and biasing the high-voltage electrode to derive the ions from the ionization region of ionizer 122, to form a GCIB 128. Accelerator power supply 140 provides V _Acc and biases the high voltage electrode with respect to ionizer 122 to provide acceleration energy equal to V _Acc electron volts. Lens power supply (e.g., 142 and 144) to focus the GCIB128 by biasing the high voltage electrode at a potential (e.g., _{V L1} and _{V L2).}
[0016]
In the present invention, the intraocular lens (IOL) 10 that is processed by the GCIB processor 100 is held by the target object holder 150 and is located in the passage of the GCIB 128. To enable a uniform smoothing of the IOL 10, the target object holder 150 is designed as follows.
[0017]
In order to perform the best IOL 10 smoothing using GCIB, the non-planar IOL surface shown in FIG. 2 must be positioned within a specified angle tolerance with respect to the orthogonal beam incidence angle. This involves adjusting the lens fixture and target object holder to correct all non-planar surfaces within their tolerance angle of error at a constant exposure level to provide process optimization and homogeneity. There must be. Lenses 10 including surfaces that are exposed to the processing beam at angles greater than ± 15 ° from normal incidence require adjustment. In particular, when smoothing the IOL 10, the target object holder 150 is rotated and adjusted by a mechanism 152 at the end of the GCIB processor 100. The rotation / adjustment mechanism 152 preferably rotates 360 ° about the long axis 154 and provides sufficient device adjustment about an axis 156 that is perpendicular to the axis 154 so that the surface of the lens 10 is ± Keep within 15 °.
[0018]
Under certain conditions, depending on the size of the IOL 10, the use of a scanning system is desirable to provide uniform smoothness. Although not required for GCIB processing, two pairs of orthogonal electrostatic scan plates 130 and 132 are utilized to create long processing area rasters or other patterns. When the beam scan is performed, the scan generator 156 provides the X-axis and Y-axis scan signal voltages to the pair of scan plates 130 and 132 via the read destination pairs 158 and 160. The scan signal voltage is a triangular wave having a different frequency, and converts the GCIB 128 into a scan-processed GCIB to scan the entire surface of the IOL 10.
[0019]
When beam scanning is not desired, processing is generally limited to the area defined by the beam diameter. The beam diameter is set by selecting the voltage (V _L1 and V _L2 ) of the power supply (eg, 142 and 144) to provide the desired beam diameter for the target object.
[0020]
According to the present invention, the surface smoothness of the intraocular lens 10 can be improved. The surface of the acrylic IOL 10 before the GCIB treatment had minute roughness. Surface roughness was 46.5 _Å, 59.4 Å in _{R RMS} with _{R a.} These roughnesses have raised the problem of surface microroughness at the cellular level causing postoperative symptoms. The surface of the acrylic IOL 10 after the GCIB treatment reduced the surface roughness without causing any structural changes in the lens itself. Surface roughness after GCIB processing is 22.6 Å in _{R a,} was 28.9 Å with _{R RMS.}
[0021]
Although the present invention has been described using several embodiments, the invention is capable of further embodiments within the spirit and scope of the appended claims.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a gas cluster ion beam processing system of the present invention.
FIG. 2 is a partially exploded view of the gas cluster ion beam processing system, showing an object holder.
FIG. 3 is an atomic microscope image showing the IOL surface before GCIB processing.
FIG. 4 is an atomic microscope image showing the surface of the IOL after GCIB processing.

Claims (10)

An apparatus for improving the surface of an intraocular lens by gas cluster ion beam processing,
A vacuum vessel,
A gas cluster ion beam source for generating a gas cluster ion beam operatively associated with the vacuum vessel;
An accelerator for accelerating the gas cluster ion beam along the gas cluster path;
An intraocular lens holder provided along the advancing axis within the gas cluster passage for positioning and holding the intraocular lens for gas cluster ion processing;
The intraocular lens holder and the intraocular lens are operably connected to the intraocular lens holder, and the intraocular lens holder and the intraocular lens are rotated around the traveling axis, and the intraocular lens holder and the intraocular lens are positioned around an axis perpendicular to the traveling axis. Position adjusting means for adjusting,
An apparatus characterized by comprising: 2. The apparatus according to claim 1, wherein the position adjustment device adjusts the positions of a plurality of regions of the intraocular lens, and intercepts the gas cluster ion beam so as to have a beam incident angle perpendicular to the intraocular lens. 3. The apparatus according to claim 2, wherein the beam incident angle is ± 15 [deg.] Perpendicular. 2. The apparatus according to claim 1, further comprising scanning means for relatively scanning the gas cluster ion beam and the intraocular lens. The apparatus of claim 1, wherein the gas cluster ion beam treatment smoothes the surface of the intraocular lens. The apparatus of claim 1, wherein the gas cluster ion beam processing smooths the edges of the intraocular lens. A method of improving the surface of an intraocular lens by gas cluster ion beam processing,
Forming an inert gas cluster ion beam in a vacuum chamber;
Accelerating the gas cluster ion beam;
Adjusting the position of the surface of the intraocular lens in the vacuum chamber to receive the gas cluster ion beam for processing;
Irradiating the surface of the intraocular lens with a predetermined dose of a gas cluster ion beam having a predetermined energy,
A method characterized by being provided including: The method of claim 7, further comprising adjusting the position of the surgical implant to smooth the surface of the intraocular lens. The method of claim 7, further comprising the step of adjusting the position of the intraocular lens and smoothing edges of the intraocular lens. Adjusting the position of the surgical implant and processing the area of the intraocular lens;
Illuminating the intraocular lens with a gas cluster ion beam at an angle of incidence perpendicular to the intraocular lens;
The method of claim 7, further comprising: